The University of Illinois at Urbana-Champaign (UIUC) and Trimeric Corporation have teamed to develop a novel biphasic absorption process with multiple stages of liquid–liquid phase separation for post-combustion carbon dioxide (CO₂) capture. The process uses a biphasic solvent that allows the formation and development of dual-liquid phases, with the absorbed CO₂ concentrated in one phase. Key features of this process include: 1) a unique process configuration of multi-stage CO₂ absorption and phase transition allows continual separation and removal of the CO₂-enriched liquid phase, thus maintaining a low CO₂ loading (i.e., rapid kinetics) and low solvent viscosity throughout CO₂ absorption; 2) only the CO₂-enriched liquid phase is used for CO₂ desorption, thus lowering the mass flow of solvent required for regeneration; and 3) a combination of flash and CO₂ stripping operations allows the high pressure of CO₂ desorption to further improve the energy efficiency. A preliminary process analysis revealed this process has potential to minimize energy and reduce costs compared with the benchmark monoethanolamine approaches. The overall project goal is to show the technical advantages of the process and generate engineering and scale-up data. Laboratory- and small bench-scale absorption and desorption column testing with simulated coal-derived flue gas will be performed to evaluate the new multi- stage process concept of combined CO₂ absorption and phase separation and the performance of high-pressure CO₂ flash and stripping operations. The results will be used to develop an optimized process flow sheet and conduct a techno-economic study for a conceptual 550-MWe coal-fired power plant retrofitted with the technology.